Radio communication system base station and mobile station

ABSTRACT

A radio communication system includes a base station of a radio communication system A, a base station of a radio communication system B operation in non-synchronized way with the base station, and a mobile station capable of communicating with both of the radio communication system A and the radio communication system B. The base station includes a radio unit for transmitting/receiving a radio wave to/from the mobile station and a system information estimation unit for estimating the system information on the radio communication system B and outputting the system estimation information. The radio unit of the base station reports the system estimation information on the base station to the mobile station. The mobile station receives the system estimation information on the base station in advance so as to perform effective switching without using a cabled connection from the radio communication system A to the radio communication system B via a relay device or the like.

This application is a U.S. National Phase Application of PCTInternational Application PCT/JP2004/014888.

TECHNICAL FIELD

The present invention relates to a plurality of separate radiocommunication systems, a base station of a radio communication system,and a mobile station capable of communications with a plurality ofseparate radio communication systems.

BACKGROUND ART

A radio communication system of a previous type is described inJP-A-2000-92541. FIG. 9 shows the previous-type radio communicationsystem described in the patent publication. In FIG. 9, the previous-typeradio communication system is configured to include a multi-mode radio801, a cable network 802, a cable telephone 803, a network 804 for aradio communication system A, a base station 805 for the radiocommunication system A, a cell 806 for the radio communication system A,a network 807 for a radio communication system B, a base station 808 forthe radio communication system B, a cell 809 for the radio communicationsystem B, and a relay device 810 for relay use between the base station805 of the radio communication system A and the base station 808 of theradio communication system B.

The multi-mode radio 801 is available for communications with the radiocommunication systems A and B. The cell 806 of the radio communicationsystem A and the cell 809 of the radio communication system B are inclose proximity to each other or overlapping each other. The basestation 805 of the radio communication system A transmits, to the basestation 808 of the radio communication system B via the relay device810, monitor information about monitoring of information such as channeloccupation or position registration in the cell at appropriate timeintervals, and system information about control channel or others in theradio communication system A. Similarly, the base station 808 of theradio communication system B also transmits, to the base station 805 ofthe radio communication system A via the relay device 810, the monitorinformation about monitoring of information such as channel occupationor position registration in the cell at appropriate time intervals, andthe system information about control channel or others in the radiocommunication system B.

When the multi-mode radio 801 in a standby status for communications orincoming calls in the radio communication system A moves into the cell806 of the radio communication system A, the base station 805 of theradio communication system A forwards the monitor information and thesystem information about the radio communication system B provided bythe base station 808 of the radio communication system B to themulti-mode radio 801.

This is expected to allow the multi-mode radio 801 to have the monitorinformation and the system information in advance about the base stationof the radio communication system being available for switching, andutilizing such information is expected to facilitate switching to theradio communication system B.

The problem with such a previous-type radio communication system isthat, for the multi-mode radio 801 to receive information from the basestation 808 of the radio communication system B being a switchingdestination, the base station 808 of the radio communication system B isrequired to provide information to the base station 805 of the radiocommunication system A via the relay device 810. For the purpose, acable connection has to be established between the base stations 805 and808 via the relay device 810. Moreover, when a radio communicationsystem C is newly provided with a base station in the cell 806 of theradio communication system A and in the cell 809 of the radiocommunication system B, a relay device is required to be newly providedto establish a cable connection to provide system information about theradio communication system C to the base station 805 of the radiocommunication system A and the base station 808 of the radiocommunication system B.

DISCLOSURE OF THE INVENTION

An object of the present invention is to provide a radio communicationsystem being capable of switching, not requiring a cable connectionamong a plurality of separate radio communication systems via a relaydevice or others.

Firstly, a radio communication system of the present invention includes:a base station of a first radio communication system; a base station ofa second radio communication system including a cell being in closeproximity to or overlapping a cell for communications by the basestation of the first radio communication system, and operatingasynchronous to the base station of the first radio communicationsystem; and a mobile station capable of communications with both thefirst and second radio communication systems. The mobile stationincludes: a radio section that receives a radio wave from each of thefirst and second radio communication systems; and a system informationdetection section that detects system information of the second radiocommunication system, and outputs system detection information. The basestation of the first radio communication system includes a storagesection that stores the system detection information provided by themobile station. A switching is made between separate radio systems byinforming the system detection information from the base station of thefirst radio communication system to the mobile station in the cell forcommunications by the base station of the first radio communicationsystem.

In the present invention, this enables effective switching between anyseparate radio communication systems without requiring a connection viaa relay device or others. Even when a new base station is provided, theexistence of the base station can be autonomously detected throughdetection of system information of the radio communication system.

Secondly, in the first invention, in the radio communication system ofthe present invention, the mobile station includes a position detectionsection that detects position information of the mobile station. Thebase station of the first radio communication system includes a storagesection that stores the system detection information and the positioninformation provided by the mobile station. A switching is made betweenthe separate radio systems by informing the system detection informationand the position information from the base station of the first radiocommunication system to the mobile station in the cell forcommunications by the base station of the first radio communicationsystem.

In the present invention, this enables effective switching to anydifferent communication-available radio communication system at theposition where the mobile station is located.

Thirdly, a radio communication system of the present invention includes:a base station of a first radio communication system; a base station ofa second radio communication system including a cell being in closeproximity to or overlapping a cell for communications by the basestation of the first radio communication system, and operatingasynchronous to the base station of the first radio communicationsystem; and a mobile station capable of communications with both thefirst and second radio communication systems. The mobile stationincludes: a radio section that receives a radio wave from each of thefirst and second radio communication systems; and a system informationestimation section that estimates system information of the second radiocommunication system, and outputs system estimation information. Thebase station of the first radio communication system includes a storagesection that stores the system estimation information provided by themobile station. A switching is made between separate radio communicationsystems by informing the system estimation information from the basestation of the first radio communication system to the mobile station inthe cell for communications by the base station of the first radiocommunication system.

In the present invention, this enables effective switching between anyseparate radio communication systems without requiring a connection viaa relay device or others. Even when a new base station is provided, theexistence of the base station can be autonomously estimated throughestimation of system information of the radio communication system.

Fourthly, in the third invention, in the radio communication system ofthe present invention, the mobile station includes a position detectionsection that detects position information of the mobile station. Thebase station of the first radio communication system includes a storagesection that stores the system estimation information and the positioninformation provided by the mobile station. A switching is made betweenthe separate radio communication systems by informing the systemestimation information and the position information from the basestation of the first radio communication system to the mobile station inthe cell for communications by the base station of the first radiocommunication system.

In the present invention, this enables effective switching to anydifferent communication-available radio communication system at theposition where the mobile station is located.

Fifthly, in the second or fourth invention, in the radio communicationsystem of the present invention, the position detection section detectsabsolute position information.

In the present invention, this enables the mobile station to detect theabsolute position information.

Sixthly, in the second or fourth invention, in the radio communicationsystem of the present invention, the position detection section detectsrelative position information.

In the present invention, this enables the mobile station to detect therelative position information from the base station.

Seventhly, a base station of the present invention includes: a firstbase station of a first radio communication system; a second basestation of a second radio communication system including a cell being inclose proximity to or overlapping a cell for communications by the firstbase station, and operating asynchronous to the first base station; anda mobile station capable of communications with both the first andsecond radio communication systems. The first base station includes: another system reception section that receives a radio wave from thesecond base station; a system information estimation section thatestimates system information of the second radio communication systemfrom an output of the other system reception section; and a storagesection that stores system estimation information being an output of thesystem information estimation section. A switching is made betweenseparate radio communication systems by informing the system estimationinformation of the second base station from the first base station tothe mobile station in communications with the first base station.

In the present invention, this enables effective switching between anyseparate radio communication systems without requiring a connection viaa relay device or others. Even when a new base station is provided, theexistence of the base station can be autonomously estimated throughestimation of system information of the radio communication system.

Eighthly, a mobile station of the present invention is capable ofcommunications with both a base station of a first radio communicationsystem, and a base station of a second radio communication systemincluding a cell being in close proximity to or overlapping a cell forcommunications by the base station of the first radio communicationsystem, and operating asynchronous to the base station of the firstradio communication system. The mobile station includes: a radio sectionthat receives a radio wave from each of the first and second radiocommunication systems; and a system information detection section thatdetects system information of the second radio communication system, andoutputs system detection information. For communications with the basestation of the first radio communication system, a switching is madebetween separate radio communications systems by informing the systemdetection information to the base station of the first radiocommunication system.

In the present invention, this enables effective switching between anyseparate radio communication systems without requiring a connection viaa relay device or others. Even when a new base station is provided, theexistence of the base station can be autonomously detected throughdetection of system information of the radio communication system.

Ninthly, in the eighth invention, the mobile station of the presentinvention includes a position detection section that detects positioninformation of the mobile station. For communications with the basestation of the first radio communication system, a switching is madebetween the separate radio communication systems by informing the systemdetection information and the position information to the base stationof the first radio communication system.

In the present invention, this enables effective switching to anydifferent communication-available radio communication system at theposition where the mobile station is located.

Tenthly, in the ninth invention, in the mobile station of the presentinvention, the position detection section detects absolute positioninformation.

In the present invention, this enables the mobile station to detect theabsolute position information.

Eleventhly, in the ninth invention, in the mobile station of the presentinvention, the position detection section detects relative positioninformation from the base station.

In the invention, this enables the mobile station to detect the relativeposition information from the base station.

Twelfthly, the mobile station of the present invention is capable ofcommunications with both a base station of a first radio communicationsystem, and a base station of a second radio communication systemincluding a cell being in close proximity to or overlapping a cell forcommunications by the base station of the first radio communicationsystem, and operating asynchronous to the base station of the firstradio communication system. The mobile station includes: a radio sectionthat receives a radio wave from each of the first and second radiocommunication systems; a system information detection section thatdetects system information of the second radio communication system, andoutputs system detection information; and a storage section that storesthe system detection information output from the system informationdetection section. A switching is made between separate radiocommunication systems by storing the system detection information in thestorage section when no communications are going on with the basestation of the first radio communication system, and by informing thesystem detection information stored in the storage section to the basestation of the first radio communication system when communications arethrough with the base station of the second radio communication system.

In the present invention, this enables effective switching between anyseparate radio communication systems without requiring a connection viaa relay device or others. Even when a new base station is provided, theexistence of the base station can be autonomously detected throughdetection of system information of the radio communication system. Whenno communications are going on with the base station of the first radiocommunication system, the system information of the second radiocommunication system is stored in the storage section so that aswitching can be made to the first radio communication system whencommunications are through with the base station of the second radiocommunication system.

Thirteenthly, in the twelfth invention, the mobile station of thepresent invention includes a position detection section that detectsposition information of the mobile station. A switching is made betweenthe separate radio communication systems by storing the system detectioninformation in the storage section when no communications are going onwith the base station of the first radio communication system, and byinforming the system detection information and the position informationstored in the storage section to the base station of the first radiocommunication system when communications are through with the basestation of the second radio communication system.

In the present invention, this enables effective switching to anydifferent communication-available radio communication system at theposition where the mobile station is located.

Fourteenthly, in the thirteenth invention, in the mobile station of thepresent invention, the position detection section detects absoluteposition information.

In the present invention, this enables the mobile station to detect theabsolute position information.

Fifteenthly, in the thirteenth invention, in the mobile station of thepresent invention, the position detection section detects relativeposition information from the base station.

In the present invention, this enables the mobile station to detect therelative position information from the base station.

Sixteenthly, a mobile station of the present invention is capable ofcommunications with both a base station of a first radio communicationsystem, and a base station of a second radio communication systemincluding a cell being in close proximity to or overlapping a cell forcommunications by the base station of the first radio communicationsystem, and operating asynchronous to the base station of the firstradio communication system. The mobile station includes: a radio sectionthat receives a radio wave from each of the first and second radiocommunication systems; and a system information estimation section thatestimates system information of the second radio communication system,and outputs system estimation information. For communications with thebase station of the first radio communication system, a switching ismade between separate radio communication systems by informing thesystem estimation information to the base station of the first radiocommunication system.

In the present invention, this enables effective switching between anyseparate radio communication systems without requiring a connection viaa relay device or others. Even when a new base station is provided, theexistence of the base station can be autonomously estimated throughestimation of system information of the radio communication system.

Seventeenthly, in the sixteenth invention, the mobile station of thepresent invention includes a position detection section that detectsposition information of the mobile station. For communications with thebase station of the first radio communication system, a switching ismade between the separate radio communication systems by informing thesystem estimation information and the position information to the basestation of the first radio communication system.

In the present invention, this enables effective switching to anydifferent communication-available radio communication system at theposition where the mobile station is located.

Eighteenthly, in the seventeenth invention, in the mobile station of thepresent invention, the position detection section detects absoluteposition information.

In the present invention, this enables the mobile station to detect theabsolute position information.

Nineteenthly, in the seventeenth invention, in the mobile station of thepresent invention, the position detection section detects relativeposition information from the base station.

In the present invention, this enables the mobile station to detect therelative position information from the base station.

Twentiethly, a mobile station of the invention is capable ofcommunications with both a base station of a first radio communicationsystem, and a base station of a second radio communication systemincluding a cell being in close proximity to or overlapping a cell forcommunications by the base station of the first radio communicationsystem, and operating asynchronous to the base station of the firstradio communication system. The mobile station includes: a radio sectionthat receives a radio wave from each of the first and second radiocommunication systems; a system information estimation section thatestimates system information of the second radio communication system,and outputs system estimation information; and a storage section thatstores the system estimation information output from the systeminformation estimation section. A switching is made between separateradio communication systems by storing the system estimation informationin the storage section when no communications are going on with the basestation of the first radio communication system, and by informing thesystem estimation information stored in the storage section to the basestation of the first radio communication system when communications arethrough with the base station of the second radio communication system.

In the present invention, this enables effective switching between anyseparate radio communication systems without requiring a connection viaa relay device or others. Even when a new base station is provided, theexistence of the base station can be autonomously estimated throughestimation of system information of the radio communication system. Whenno communications are going on with the base station of the first radiocommunication system, the system information of the second radiocommunication system is stored in the storage section so that aswitching can be made to the first radio communication system whencommunications are through with the base station of the second radiocommunication system.

Twenty-firstly, in the twentieth invention, the mobile station of thepresent invention includes a position detection section that detectsposition information of the mobile station. A switching is made betweenthe separate radio communications systems by storing the systemestimation information in the storage section when no communications aregoing on with the base station of the first radio communication system,and by informing the system estimation information and the positioninformation stored in the storage section to the base station of thefirst radio communication system when communications are through withthe base station of the second radio communication system.

In the present invention, this enables effective switching to anydifferent communication-available radio communication system at theposition where the mobile station is located.

Twenty-secondly, in the twenty-first invention, in the mobile station ofthe present invention, the position detection section detects absoluteposition information.

In the present invention, this enables the mobile station to detect theabsolute position information.

Twenty-thirdly, in the twenty-first invention, in the mobile station ofthe present invention, the position detection section detects relativeposition information from the base station.

In the present invention, this enables the mobile station to detect therelative position information from the base station.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic diagram of a radio communication system in a firstembodiment of the present invention.

FIG. 2 is a block diagram showing an exemplary configuration of a basestation of a radio communication system A in the first embodiment of thepresent invention.

FIG. 3 is a schematic diagram of a radio communication system in asecond embodiment of the invention.

FIG. 4 is a block diagram showing an exemplary configuration of a mobilestation in the second embodiment of the invention.

FIG. 5 is a block diagram showing an exemplary configuration of a basestation of a radio communication system A in the second embodiment ofthe present invention.

FIG. 6 is a schematic diagram of a radio communication system in a thirdembodiment of the present invention.

FIG. 7 is a block diagram showing an exemplary configuration of a mobilestation in the third embodiment of the present invention.

FIG. 8 is a block diagram showing an exemplary configuration of a basestation of a radio communication system A in the third embodiment of thepresent invention.

FIG. 9 is a schematic diagram of a radio communication system of aprevious type.

BEST MODE FOR CARRYING OUT THE INVENTION

In the below, embodiments of the present invention are described byreferring to the accompanying drawings.

First Embodiment

A first embodiment of the present invention is an example in which abase station of a radio communication system autonomously estimates theexistence of other radio communication systems, and informs theresulting information about the estimated radio communication systems toinside of the cell of its own system.

FIG. 1 is a schematic diagram of a radio communication system in thefirst embodiment of the present invention. In FIG. 1, a mobile station101 is capable of communications with both a first radio communicationsystem A and a second radio communication system B. A base station 104of the radio communication system A communicates with any mobile stationavailable for communications with the radio communication system A in acell 105. A base station 106 of the radio communication system Bcommunicates with any mobile station available for communications withthe radio communication system B in a cell 107. The base stations 104and 106 are not connected to each other over a cable, via a relaystation, or others, and are operating asynchronous to each other.Herein, exemplified is a case where the radio communication system A isof a CDMA cellular mode, and the radio communication system B is of aGSM cellular mode. The cells 105 and 107 are positioned in closeproximity to or overlapping each other. The mobile station 101 islocated in an area where the cells 105 and 107 are overlapping eachother, is connected with the base station 104, and is in a standbystatus for communications or incoming calls.

FIG. 2 is a diagram showing an exemplary configuration of the basestation 104 of the radio communication system A. In FIG. 2, the basestation 104 is configured to include a radio section 201 that transmitsand receives radio waves to/from the mobile station 101, a controlsection 202 that exercises control over signals coming and going from/tothe radio section 201, and an other system estimation section 203 thatestimates other radio communication systems. The radio section 201 andthe other system estimation section 203 are connected to each other viathe control section 202. The other system estimation section 203 isprovided with an other system reception section 204 that receives radiowaves coming from the base station 106 of the radio communication systemB, a system information estimation section 205 that estimates systeminformation of the radio communication system B, and a storage section207 that stores system estimation information 206 being an output of thesystem information estimation section 205. The other system receptionsection 204 is connected to the system information estimation section205. The system information estimation section 205 is connected with thestorage section 207. The storage section 207 is connected with thecontrol section 202. The other system reception section 204 receivesradio waves coming from the base station 106 of the radio communicationsystem B, and forwards a reception signal to the system informationestimation section 205.

The system information estimation section 205 estimates the existence ofthe radio communication system B from information about the receptionsignal provided by the other system reception section 204, e.g.,frequency band, channel width, slot interval, average power, peakfactor, or hopping pattern. In the first embodiment of the invention,for example, because the radio communication system B is of GSM mode,the frequency band of the reception signal is any one of 450 MHz band,480 MHz band, 850 MHz band, 900 MHz band, 1800 MHz band, and 1900 MHzband, and the channel width is 200 kHz. Such information is stored inadvance in the system information estimation section 205, and the systeminformation estimation section 205 performs scanning to see in whichfrequency band the reception signal is located. By checking thebandwidth of the reception signal, it becomes possible to estimatewhether the radio communication system B is of GSM mode or not. Thesystem information estimation section 205 outputs information about theestimated system as the system estimation information 206, and inputsthe information into the storage section 207. The system estimationinformation 206 includes, for example, the communications mode of theestimated radio communication system (GSM mode in the example of thefirst embodiment), the frequency band in use by the estimated radiocommunication system, the channel frequency in use by the base station106, and others. The storage section 207 transfers the system estimationinformation 206 in storage to the control section 202. By the radiosection 201, the control section 202 informs the mobile station 101 ofthe system estimation information 206 provided by transfer from thestorage section 207 using an information channel in use by the basestation 104 of the radio communication system A. The mobile station 101provided by the system estimation information 206 in advance from thebase station 104 about the base station 106 of the radio communicationsystem B as such can make effective switching from the radiocommunication system A to the radio communication system B.

Even when a new base station is provided to the radio communicationsystem B, the base station 104 can autonomously estimate the existenceof the base station by receiving radio waves of the base station newlyprovided to the radio communication system B, and by estimating itssystem information.

Note here that, other than being transferred over the informationchannel in use by the base station 104, the system estimationinformation 206 may be transferred as a part of data of any upper layerapplication.

Alternatively, the other system reception section 204 may receive radiowaves from radio communication systems other than the radiocommunication system B. The system information estimation section 205may estimate system information not belonging to the radio communicationsystem B. With this being the case, the base station 104 of the radiocommunication system A can inform the existence of a plurality of radiocommunication systems.

Even when a new base station is provided not to the radio communicationsystem B but to any other radio communication system, the base station104 can autonomously estimate the existence of the base station byreceiving radio waves of the base station newly provided not to theradio communication system B but to any other radio communicationsystem, and by estimating its system information.

The base station includes a cellular or wireless LAN access point, orradio communication system in which base stations are of a similar cellsize, for example.

The radio section 201 and the other system reception section 204 may beconfigured using a single multi-mode radio section, and thetime-division technique may be applied for communications between mobilestations, and estimation of other radio communication systems. With thisbeing the case, for example, the scanning operation may be performed forthe radio communication system B while the radio communication system Ais in an idle state for communications.

As an alternative configuration, a sector antenna may be used for anantenna of the base station 104, and every sector may be estimated withany other radio communication system, and system estimation informationabout any other radio communication system may be informed to everysector.

For switching by the mobile station among the radio communicationsystems, a switching may be made at a user's discretion withdetermination criteria of the fee, communications speed, or others ofthe radio communication system. Or the switching may be madeautomatically by the mobile station itself with a determinationcriterion of channel vacancy and power consumption of the radiocommunication system.

As described in the foregoing, in the first embodiment of the presentinvention, the base station of the radio communication system A receivesradio waves from the base station of any other communications system,and estimates the other radio communication system. This allowsswitching among separate radio communication systems without a cableconnection via a relay device or others, allows estimation of theexistence of radio communication systems if newly provided, and allowseffective switching among separate radio communication systems.

Second Embodiment

A second embodiment of the invention is an example in which, in an areawhere a radio communication system A with a wider communications cell(e.g., cellular phone) is in close proximity to or overlapping with aradio communication system B with a narrower communications cell (e.g.,wireless LAN), a mobile station transmits system information of thecommunicated radio communication system B and the position informationat the time of communications to the base station of the radiocommunication system A, and the base station of the radio communicationsystem A informs the system information and the position information ofthe radio communication system B into the cell. By referring to FIGS. 3to 5, such an example is described.

FIG. 3 is a schematic diagram of a radio communication system in thesecond embodiment of the present invention. In FIG. 3, a mobile station301 is capable of communications with both the first and second radiocommunication systems A and B, and is capable of detecting its owncurrent position. A base station 302 of the radio communication system Acommunicates with the mobile station 301 being available forcommunications with the radio communication system A in a cell 303. Abase station 304 of the radio communication system B communicates withthe mobile station 301 being available for communications with the radiocommunication system B in a cell 305. The base stations 302 and 304 arenot connected to each other over a cable, via a relay device, or others,and are operating asynchronously. Herein, as an example, the radiocommunication system B is assumed as being wireless LAN in an IEEE802.11 system. The cell 305 is smaller compared with the cell 303, andis proximity thereto or overlapping therewith.

FIG. 4 is a block diagram showing an exemplary configuration of themobile station 301. In FIG. 4, the mobile station 301 is provided with afirst radio section 401 capable of communications with the radiocommunication system A, a second radio section 402 capable ofcommunications with the radio communication system B, a positiondetection section 403 capable of detecting its own current position, anda control section 404 carrying therein a system information detectionsection 405 and a storage section 406. The first and second radiosections 401 and 402 are connected to the system information detectionsection 405 and the storage section 406, respectively. The positiondetection section 403 is connected to the storage section 406. Theposition detection section 403 detects absolute positions using a GPS,or detects relative positions based on delay amounts or others from aplurality of base stations of the radio communication system A.

When the mobile station 301 is connected to the base station 304 of theradio communication system B, a signal received by the second radiosection 402 is input to the system information detection section 405.From thus input reception signal, the system information detectionsection 405 detects system information such as SSID (service setidentifier, a key for network identification) of the base station 304,or mode (infrastructure mode or ad hoc mode) for output to the storagesection 406. The storage section 406 stores, as system detectioninformation, information combining the output system information and theposition information being an output of the position detection section403 when the system information is output.

When the mobile station 301 is in communications with the base station304 of the radio communication system B, and is in a standby status withrespect to the base station 302 of the radio communication system A, thecontrol section 404 outputs the system detection information from thestorage section 406 to the first radio section 401, and transmits theinformation to the base station 302 using the control channel of thebase station 302.

When the mobile station 301 is in communications with the base station304 of the radio communication system B, and when no communications aregoing on at all with the base station 302 of the radio communicationsystem A, the storage section 406 stores the system detectioninformation. When the mobile station 301 is through with communicationswith the base station 304 of the radio communication system B, and whena connection is established with the base station 302 of the radiocommunication system A, the control section 404 outputs the systemdetection information stored in the storage section 406 to the firstradio section 401, and transmits the information to the base station 302using the control channel of the base station 302.

FIG. 5 is a diagram showing an exemplary configuration of the basestation 302 of the radio communication system A. In FIG. 5, the basestation 302 is provided with a radio section 501 that transmits andreceives radio waves to/from the mobile station 301, and a controlsection 502 carrying therein a storage section 503, and exercisescontrol over signals incoming and going from/to the radio section 501.The storage section 503 stores the system detection information providedby the mobile station 301.

When the mobile station 301 is connected with the base station 302 ofthe radio communication system A, and when no communications are goingon at all with the base station 304 of the radio communication system B,the control section 404 transmits the position information to the basestation 302 using the control channel of the base station 302. Based onthus provided position information, the control section 502 searches thestorage section 503 for system detection information showing a match tothe position information, and informs the system information of theradio communication system B at the position where the mobile station301 is located. The mobile station 301 provided in advance with thesystem detection information from the base station 302 of the radiocommunication system A about the base station 304 of the radiocommunication system B as such can perform effective switching from theradio communication system A to the radio communication system B.

Even when any new base station is provided to the radio communicationsystem B, the mobile station 301 can autonomously detect the existenceof the base station by communicating with the newly-provided basestation of the radio communication system B, and by detecting its systeminformation. The base station 302 can autonomously accumulate the systemdetection information of the newly-provided base station in the storagesection 503.

By the base station 302 deriving the system detection information assuch from a plurality of mobile stations, the storage section 503 of thebase station 302 can store the correct area range of the cell 305 forcommunications for the base station 304 so that the information aboutthe existence of the radio system B can be informed with more precision.

Exemplified herein is the case of informing the system information ofthe base station 304 of the radio communication system B using the radiocommunication system A. On the contrary, the system information of thebase station 302 of the radio communication system A may be informedusing the radio communication system B.

Note here that the first and second radio sections 401 and 402 of themobile station 301 may transmit and receive radio waves to/from theradio communication systems other than the radio communication systems Aand B. Moreover, the system information detection section 405 may detectsystem information of the radio communication systems other than theradio communication system B, and may output system information of aplurality of radio communication systems. With this being the case, thebase station 302 of the radio communication system A can inform theexistence of a plurality of radio communication systems.

The base station 301 can autonomously detect the existence of anynewly-provided base station provided not to the radio communicationsystem B but to any other radio communication system, and the basestation 302 can autonomously accumulate the system detection informationof the newly-provided base station into the storage section 503.

The first and second radio sections 401 and 402 are configured by asingle multi-mode radio section, and may access the radio communicationsystems A and B in a time division manner.

Note that, other than being transferred over the control channel, thesystem detection information may be transferred as a part of data of anyupper layer application. At this time, the system information of anyother radio communication system in the cell 303 may be transferred fromthe base station 302 as a part of data of the application, and based onthe position information of the mobile station 301 in the mobile station301, the system information of any other radio communication system maybe searched.

When the mobile station makes a switching of radio communicationsystems, the switching may be made at a user's discretion withdetermination criteria of the fee, communications speed, or others ofthe radio communication system. Or the switching may be madeautomatically by the mobile station itself with a determinationcriterion of channel vacancy and power consumption of the radiocommunication system.

As described in the foregoing, in the second embodiment of the presentinvention, a switching can be made among any separate radiocommunication systems without a cable connection via a relay device orothers by a mobile station detecting system information of other radiocommunication systems through reception of radio waves from the basestations of the radio communication systems, and by the mobile stationtransmitting the system detection information to the base station of theradio communication system A. Further, the existence of anynewly-provided radio communication system can be autonomously detectedso that switching can be effectively made among any separate radiocommunication systems.

Third Embodiment

A third embodiment of the present invention is an example in which amobile station in communications with the radio communication system Aautonomously estimates the existence of other radio communicationsystems, the resulting information of the estimated other radiocommunication systems is transmitted to the base station of the radiocommunication system A, and the base station of the radio communicationsystem A informs the system information of the radio communicationsystem B into the cell. In the below, FIGS. 6 to 8 are referred to fordescription.

FIG. 6 is a schematic diagram of a radio communication system in a thirdembodiment of the present invention. In FIG. 6, a mobile station 601 iscapable of communications with both the first and second radiocommunication systems A and B. The base station 108 of the radiocommunication system A communicates with the mobile station 601 beingavailable for communications with the radio communication system A inthe cell 105. The base station 106 of the radio communication system Bcommunicates with the mobile station 601 being available forcommunications with the radio communication system B in the cell 107.The base stations 108 and 106 are not connected to each other over acable or via a relay device or others, and operating asynchronous toeach other. Herein, exemplified is a case where the radio communicationsystem A is of a CDMA cellular mode, and the radio communication systemB is of a GSM cellular mode. The cells 105 and 107 are positioned inclose proximity to or overlapping each other. The mobile station 601 islocated in an area where the cells 105 and 107 are overlapping eachother, is connected with the base station 108, and is in communicationstherewith.

FIG. 7 is a block diagram of an exemplary configuration of the mobilestation 601. In FIG. 7, the mobile station 601 is provided with a firstradio section 602 capable of communications with the radio communicationsystem A, a second radio section 603 capable of communications with theradio communication system B, a position detection section 604 capableof detecting its own current position, and a control section 605carrying therein a system information estimation section 606 and astorage section 607. The first and second radio sections 602 and 603 areconnected to the system information estimation section 606 and thestorage section 607, respectively. The position detection section 604 isconnected to the storage section 607. The position detection section 604detects absolute positions using a GPS, or detects relative positionsbased on delay amounts or others from a plurality of base stations ofthe radio communication system A. Even being in communications with thebase station 108, the mobile station 601 can receive radio waves of thebase station 106 from the second radio section 603. Note here that thesecond radio section 603 is not necessary to be always in the receptionstate, and may be turned into the reception state after a certain periodof time.

The system information estimations section 606 estimates the existenceof the radio communication system B from information about a receptionsignal provided by the base station 106, e.g., frequency band, channelwidth, slot interval, average power, peak factor, or hopping pattern. Inthe third embodiment of the present invention, for example, because theradio communication system B is of GSM mode, the frequency band for useis any one of 450 MHz band, 480 MHz band, 850 MHz band, 900 MHz band,1800 MHz band, and 1900 MHz band, and the channel width is 200 kHz. Suchinformation is stored in advance in the system information estimationsection 606, and the system information estimation section 606 performsscanning to see in which frequency band the reception signal is located.By checking the bandwidth of the reception signal, it becomes possibleto estimate whether the radio communication system B is of GSM mode ornot. The system information estimation section 606 outputs systeminformation about the estimated system to the storage section 607.Specifically, the system information includes the communications mode ofthe estimated radio communication system (GSM mode in the example of thethird embodiment), the frequency band in use by the estimated radiocommunication system, the channel frequency in use by the base station106, and others. The storage section 607 stores, as system estimationinformation, information combining the output system information and theposition information being an output of the position detection section403 when the system information is output.

When the mobile station 601 is in communications with the base station106 of the radio communication system B, and is in a standby status withrespect to the base station 108 of the radio communication system A, thecontrol section 605 outputs the system estimation information from thestorage section 607 to the first radio section 602, and transmits theinformation to the base station 108 using the control channel of thebase station 108.

When the mobile station 601 is in communications with the base station106 of the radio communication system B, and when no communications aregoing on at all with the base station 108 of the radio communicationsystem A, the storage section 607 stores the system estimationinformation. When the mobile station 601 is through with communicationswith the base station 106 of the radio communication system B, and whena connection is established with the base station 108 of the radiocommunication system A, the control section 605 outputs the systemestimation information stored in the storage section 607 to the firstradio section 602, and transmits the information to the base station 108using the control channel of the base station 108.

FIG. 8 is a diagram showing an exemplary configuration of the basestation 108 of the radio communication system A. In FIG. 8, the basestation 108 is provided with a radio section 608 that transmits andreceives radio waves to/from the mobile station 601, and a controlsection 609 carrying therein a storage section 610, and exercisescontrol over signals incoming and going from/to the radio section 608.The storage section 610 stores the system estimation information and theposition information provided by the mobile station 601. The basestation 108 informs the system estimation information stored in thestorage section 610 to the mobile station 601 in the cell 105 from theradio section 608. In this manner, the mobile station 601 provided bythe system estimation information in advance can perform switchingeffectively from the radio communication system A to the radiocommunication system B.

Even when any new base station is provided to the radio communicationsystem B, the mobile station 601 can autonomously estimate the existenceof the base station by receiving radio waves of the newly-provided basestation of the radio communication system B, and by estimating itssystem information. The base station 108 can autonomously accumulate thesystem estimation information of the newly-provided base station in thestorage section 610.

Exemplified herein is the case of informing the system estimationinformation of the base station 106 of the radio communication system Busing the radio communication system A. On the contrary, the systemestimation information of the base station 108 of the radiocommunication system A may be informed using the radio communicationsystem B.

Note here that the first and second radio sections 602 and 603 maytransmit and receive radio waves to/from the radio communication systemsother than the radio communication systems A and B. Moreover, the systeminformation estimation section 606 may estimate system information ofthe radio communication systems other than the radio communicationsystem B, and may output system estimation information of a plurality ofradio communication systems. With this being the case, the base station108 of the radio communication system A can inform the existence of aplurality of radio communication systems.

The base station 601 can autonomously estimate the existence of thenewly-provided base station not to the radio communication system B butto any other radio communication system, and the base station 108 canautonomously accumulate the system estimation information of thenewly-provided base station.

The first and second radio sections 602 and 603 are configured by asingle multi-mode radio section, and may access the radio communicationsystems A and B in a time division manner.

Note that the system estimation information may be transferred using apart of data of any upper layer application.

For switching by the mobile station among the radio communicationsystems, a switching may be made at a user's discretion withdetermination criteria of the fee, communications speed, or others ofthe radio communication system. Or the switching may be madeautomatically by the mobile station with a determination criterion ofchannel vacancy and power consumption of the radio communication system.

As described in the foregoing, in the third embodiment of the presentinvention, a switching can be made among any separate radiocommunication systems without a cable connection via a relay device orothers by a mobile station estimating system information of other radiocommunication systems through reception of radio waves from the basestations of the radio communication systems, and by the mobile stationtransmitting the system estimation information to the base station ofthe radio communication system A. Further, the existence of anynewly-provided radio communication system can be autonomously estimatedso that switching can be effectively made among any separate radiocommunication systems.

INDUSTRIAL APPLICABILITY

The present invention has effects of achieving a switching amongseparate radio communication systems without a cable connection or via arelay device or others, and effects of achieving effective switchingamong separate radio communication systems through detection of theexistence of any newly-provided radio communication system. It isconsidered useful as a radio communication system, a base station, and amobile station.

1. A radio communication system, comprising: a base station of a firstradio communication system; a base station of a second radiocommunication system including a cell being in close proximity to oroverlapping a cell for communications by the base station of the firstradio communication system, and operating asynchronous to the basestation of the first radio communication system; and a mobile stationcapable of communications with both the first and second radiocommunication systems, wherein the mobile station includes: a radiosection that receives a radio wave from each of the first and secondradio communication systems; and a system information estimation sectionthat scans a plurality of radio frequencies to determine a frequency ofthe radio wave received from the second radio communication system,determines a communication mode of the second radio communication systembased on the determined frequency, and transmits the determinedcommunication mode as system estimation information to the base stationin the first radio communication system, the base station of the firstradio communication system includes: a storage section that stores thesystem estimation information provided by the mobile station, andwherein the base station of the first radio communication systemtransmits the system estimation information to the mobile station in thecell, and the mobile station switches from the first radio communicationsystem to the second radio communication system based on the systemestimation information.
 2. The radio communication system according toclaim 1, wherein: the mobile station includes a position detectionsection that detects position information of the mobile station, thebase station of the first radio communication system includes a storagesection that stores the system estimation information and the positioninformation transmitted by the mobile station, and wherein the basestation of the first radio communication system transmits the storedsystem estimation information to the position of the mobile station inthe cell, and the mobile station switches from the first radiocommunication system to the second radio communication system based onthe system estimation information.
 3. A mobile station capable ofcommunications with both a base station of a first radio communicationsystem, and a base station of a second radio communication systemincluding a cell being in close proximity to or overlapping a cell forcommunications by the base station of the first radio communicationsystem, and operating asynchronous to the base station of the firstradio communication system, comprising: a radio section that receives aradio wave from each of the first and second radio communicationsystems; and a system information estimation section that scans aplurality of radio frequencies to determine a frequency of the radiowave received from the second radio communication system, determines acommunication mode of the second radio communication system based on thedetermined frequency, and transmits the determined communication mode assystem estimation information to the base station of the first radiocommunication system, wherein the mobile station switches from the firstradio communication system to the second radio communication systembased on the system estimation information transmitted by the basestation of the first radio communication system back to the mobilestation.
 4. The mobile station according to claim 3, comprising aposition detection section that detects position information of themobile station, wherein the mobile station transmits the positioninformation to the base station of the first radio communication system,and the mobile station switches from the first radio communicationsystem to the second radio communication system based on the systemestimation information, the system estimation information transmitted bythe base station of the first radio communication system to the mobilestation in response to receiving the position information.
 5. The mobilestation according to claim 4, wherein the position detection sectiondetects absolute position information.
 6. The mobile station accordingto claim 4, wherein the position detection section detects relativeposition information from the base station.
 7. A mobile station capableof communications with both a base station of a first radiocommunication system, and a base station of a second radio communicationsystem including a cell being in close proximity to or overlapping acell for communications by the base station of the first radiocommunication system, and operating asynchronous to the base station ofthe first radio communication system, comprising a radio section thatreceives a radio wave from each of the first and second radiocommunication systems; a system information estimation section thatscans a plurality of radio frequencies to determine a frequency of theradio wave received from the second radio communication system,determines a communication mode of the second radio communication systembased on the determined frequency, and transmits the determinedcommunication mode as system estimation information to the base stationof the first radio communication system; and a storage section thatstores the system estimation information, wherein the mobile stationstores the system estimation information in the storage section when nocommunications are going on with the base station of the first radiocommunication system, and transmits the system estimation informationstored in the storage section to the base station of the first radiocommunication system when communications with the base station of thesecond radio communication system are complete, and the mobile stationswitches from the first radio communication system to the second radiocommunication system based on the system estimation informationtransmitted by the base station of the first radio communication systemback to the mobile station.
 8. The mobile station according to claim 7,comprising a position detection section that detects positioninformation of the mobile station, wherein the mobile station stores thesystem detection information in the storage section when nocommunications are going on with the base station of the first radiocommunication system, and transmits the system estimation informationand the position information stored in the storage section to the basestation of the first radio communication system when communications arethrough with the base station of the second radio communication system,and the mobile station switches from the first radio communicationsystem to the second radio communication system based on the systemestimation information, the system estimation information transmitted bythe base station of the first radio communication system to the mobilestation in response to receiving the position information.
 9. The mobilestation according to claim 8, wherein the position detection sectiondetects absolute position information.
 10. The mobile station accordingto claim 8, wherein the position detection section detects relativeposition information from the base station.
 11. The radio communicationsystem according to claim 2, wherein the position detection sectiondetects absolute position information.
 12. The radio communicationsystem according to claim 2, wherein the position detection sectiondetects relative position information from the base station.